In many devices, such as fuel injectors, a plurality of components are positioned in contact with one another to define a high pressure space. These components are clamped together in an effort to prevent leakage through the planar sealing land between the components. In the case of fuel injectors, these components can be charged with sealing against leakage in the face of relatively high pressures, which can be on the order of 200 MPa or greater. Engineers have observed that when a leak develops between adjacent components, at such high pressures, it can sometimes act as a wedge to separate the two components creating an even larger leak path. In other words, as the leak penetrates the sealing land between the components, it remains at a relatively high pressure pushing the two components apart, which creates an even larger leak area. This action can cause even further component separation, resulting in even more leakage.
In the case of fuel injectors, this type of leakage is undesirable for several reasons. First, any leaked fuel that was at one time pressurized, arguably results in a waste of energy, since the fuel was pressurized from engine power but not injected into the same. In addition, leakage can undermine the ability to accurately predict the performance of a fuel injector. For instance, if fuel is being leaked that was expected to be injected, the fuel injector may be injecting less fuel than it should. In some fuel injectors, leakage can also reduce injection pressure. In addition, leakage can be a source of variable performance among a plurality of fuel injectors in a given engine. For instance, if each fuel injector exhibits substantially different leakage rates, that can cause differing fuel injector performance. In other words, the plurality of fuel injectors could be injecting different amounts of fuel based upon an identical set of control signals.
One previous strategy for dealing with sealing against leakage between fuel injector components with a planar interface, is to reduce the area of the planar surface so that more of the clamping load is concentrated in a smaller area. This strategy, for instance, is illustrated in co-owned U.S. Pat. No. 5,897,058, invented by Coldren et al. While such a strategy can be effective in many applications, other factors, such as spatial limitation features, can reduce the applicability of such a strategy. For instance, in some situations there may be so many fluid passageways, dow alignment bores and/or fastener bores that an implementation of a reduced sealing land area strategy can cause other undesirable effects, such as component distortion that may lead to even more leakage.
The present invention is directed to one or more of the problems set forth above.